diff --git a/src/hci.h b/src/hci.h
index e82393c3b..a8b02756c 100644
--- a/src/hci.h
+++ b/src/hci.h
@@ -109,11 +109,13 @@ extern "C" {
 #endif
 
 // additional pre-buffer space for packets to Bluetooth module, for now, used for HCI Transport H4 DMA
+#ifndef HCI_OUTGOING_PRE_BUFFER_SIZE
 #ifdef HAVE_HOST_CONTROLLER_API
 #define HCI_OUTGOING_PRE_BUFFER_SIZE 0
 #else
 #define HCI_OUTGOING_PRE_BUFFER_SIZE 1
 #endif
+#endif
 
 // BNEP may uncompress the IP Header by 16 bytes
 #ifndef HCI_INCOMING_PRE_BUFFER_SIZE